Added coderbyte array challenge

Author: AnoshaRehan

stockPicker.py

@@ -0,0 +1,35 @@
+'''
+Have the function StockPicker(arr) take the array of numbers stored
+in arr which will contain integers that represent the amount in dollars
+that a single stock is worth, and return the maximum profit that could
+have been made by buying stock on day x and selling stock on day y 
+where y > x. For example: if arr is [44, 30, 24, 32, 35, 30, 40, 38,
+15] then your program should return 16 because at index 2 the stock 
+was worth $24 and at index 6 the stock was then worth $40, so if you 
+bought the stock at 24 and sold it at 40, you would have made a profit
+of $16, which is the maximum profit that could have been made with this
+list of stock prices.
+
+If there is not profit that could have been made with the stock prices,
+then your program should return -1. For exmaple: arr is [10, 9, 8, 2]
+then your program should return -1.
+
+Examples:
+
+Input: [10, 12, 4, 5, 9]
+Output: 5
+
+'''
+
+def StockPicker(arr):
+	cost = 0
+	maxcost = 0
+	
+	mini = arr[0]
+	for i in range(len(arr)):
+		mini = min(mini, arr[i])
+		cost = arr[i] - mini
+		maxcost = max(maxcost, cost)
+	return maxcost
+	
+print(StockPicker([10, 12, 4, 5, 9])